3D Shuttle-Based Pallet ASRS for Distribution Facilities with Space Limitations

Next-generation shuttle pallet storage and retrieval systems enable automated warehouse operations, delivering flexibility, modularity and scalability.

The consumer goods industries are in the midst of a supply chain revolution. Continuous increase in the cost of land, labor and facilities has put a heightened demand on space utilization within warehouses and distribution centers.

Just-in-time delivery of smaller quantities of a larger number of products and orders to retail stores is pushing inventory storage back to the DCs and manufacturers. Manufacturers are more closely looking at their storage and how they can satisfy the needs of retailers. Along with this growth in SKUs and just-in-time delivery is an increase in the variability of primary and secondary packaging of consumer products. Packaging styles include boxes of all sizes, cans and jars in paperboard trays, open and closed cartons for beverages and bags, and large tissue packages.

Logistics executives are adjusting to these dynamics by “reconcepting” their DCs and manufacturing warehouses, looking for answers to questions like… “How can we optimize our distribution at the lowest total cost, factoring facility, labor, equipment and inventory? And, how can we reduce inbound and outbound transportation costs, and fixed and variable costs within our distribution network?”   

Automation is key

Grocery supply chain partners (including cold storage, food manufacturers, beverage and consumer products) need to provide increasingly efficient storage and throughput of high-volume, ever-changing SKU mixes to retail stores. For handling these loads, automated storage and retrieval systems (AS/RS), and other technologies are becoming more widely utilized to speed throughput, improve cost efficiency and maintain more precise product tracking.

For decades, AS/RS cranes have served as the workhorse for high-density, high-throughput automated pallet movement in distribution operations. These computer-controlled systems, which automatically deposit, store and retrieve pallet loads from defined storage locations, permit rapid and efficient pallet handling and product rotation, essential to the needs of contemporary warehouses. AS/RS stacker cranes provide single-deep, double-deep and multi-deep stacking, with the flexibility to handle one pallet load at a time or multi-loads. The latest stacker cranes can go three pallets deep with a telescope fork, and then with a satellite remote unit can run a pallet as much as 20 pallets deep, and then return back to the stacker crane. 

High-bay AS/RS optimize cubic space usage, not only by their vertical stacking capability, but also by minimizing aisle cubic footage. By eliminating the need for forklift trucks, aisles can be made narrower, allowing 12-ft-wide aisles to become just 5-ft wide. This space can then be used for more pallet positions.

But conventional warehouses without high-bay ceiling heights are typically not candidates for AS/RS, even though they may have the same requirements for high-density, high-throughput storage and distribution of pallets with a high volume of fast-moving SKUs. As demands continue to increase on modern distribution facilities, frequently the performance of conventional AS/RS systems will not provide sufficient flexibility, space utilization, throughput and cost payback to justify the investment.  

This condition is exasperated as an increasing number of supply chain manufacturers, bottlers and distributors require 24-hour operations, at maximum throughput. Without AS/RS, warehouses depend upon the accelerated use of forklifts maneuvering pallets into low-bay racking and staging for shipping, which is both labor-intensive and space-consuming.

Manual pallet handling in cold-storage warehouses can be particularly troublesome. Compared to ambient-temperature facilities, many manually operated cold-storage warehouses are plagued with a higher incidence of wrong item fulfillment and poor product rotation, which increases returns, shipping costs and labor. Cold-storage warehouses also have heightened facility, equipment and product damage, primarily caused by manually-operated forklifts impacting racks, doors, walls and product cases –higher than that found in warehouses with ambient temperatures. Personnel turnover in cold-storage warehouses is also higher than in ambient-temperature facilities. The extreme temperatures create difficult working conditions for personnel, heightened safety issues, and staff recruitment and retention problems.

Beverage bottlers are dealing with their own set of issues when it comes to manual pallet handling. Many are running their operations 24 hr/day, using mainly forklifts and manual high-density rack systems for their storage. They are struggling to find labor, and they are running out of space.

Automated shuttle-based pallet storage

An alternative to high-bay crane-based AS/RS, for warehouses with lower ceilings where high-density storage is required, an automated shuttle-based pallet storage system will deliver comparable cubic space utilization, throughput and cost efficiencies to that of high-bay crane-based AS/RS. For warehouses confronted with space restrictions, automated shuttle-based pallet storage presents a solution for the utilization of existing warehouse space, as opposed to the necessity of expanding into larger warehouse facilities to accommodate manual pallet-handling operations.

The latest generation of automated shuttle-based pallet storage systems is Rover™, manufactured by Advance Storage Products. Designed to adapt to any warehouse, no matter the size constraints, Rover is a three-dimensional, shuttle-based, automated pallet storage, retrieval and delivery system that is configurable, flexible and scalable. It employs low-footprint vertical reciprocating conveyors (VRCs) instead of fixed-aisle cranes, and enables storage locations of more than 20 pallets deep, comparable to the industry’s most dense automated pallet storage.

The system is suited for manufacturers and distributors, including those in the cold-storage food and beverage industries, whose operations demand flexible high-density storage for high-volume, limited-SKU counts. Unlike conventional racking systems or crane-based AS/RS, Rover vehicles move simultaneously and tri-directionally throughout the storage rack. The system consists of few moving components – Rover shuttles, VCRs, and a short inbound and outbound conveyor. 

For high-density storage in FIFO or LIFO configurations, multiple SKU’s can be easily stored and accessed on any aisle and any level as needed. Deep-lane and shallow-lane storage can be easily accommodated within the same racking structure, without any additional equipment, and little or no modification to the system. This supports the flexibility to change to new SKU profiles, such as to accommodate a shift away from an 80/20% mix of fast- and slow-moving SKUs to a 60/40% mix, as distribution operations require. 

Throughput is scaled by adding Rover shuttles or vertical reciprocating conveyors as needed. VCRs are a safe, economical way to raise and lower shuttles from one level to another. Expansion or reconfiguration is simplified when compared to crane-based AS/RS, because it is normally just a reconfiguration of the physical rack system, with software changes to the automation to recognize the reconfigured rack system.

Pallet movement outside of the system

The simplicity of adding track for the shuttles can extend beyond the storage locations of the Rover system, integrating to interfacing operations of receiving, pick replenishment, end-of-line production and shipping. 

As product comes off the production line, for example, pallets can be staged for delivery to the loading dock using inexpensive pallet racking or gravity-flow conveyor, instead of conventional powered conveyor. 24/7 operation of Rover allows for off-shift staging, so pallets can be sequenced for loading. When the trucks arrive, they can be quickly loaded by assigning a shuttle to constantly bring the pallets forward, where a forklift can take of the end pallets and put them into a truck.

In most warehouses, picking is the most labor-intensive function, and usually can provide the most cost savings when automated. In beverage warehouses, an average person can replenish 50 to 60 cases/hr into a carton flow. Forklift operators can perform six to eight replenishment events/hr. The Rover system can support integration to automatically replenish pick modules or layer picking operations.

One of the major causes of product damage and facility damage in warehouses is from manually operated forklift trucks moving pallet loads through the end-of-production-line and warehouse operations. 

Automated shuttle-based, pallet storage systems offer flexibility and efficiency. For manufacturers, improved productivity, reduced labor requirements and optimized utilization of space represent the system’s key benefits. 

—Edited from an article contributed by Advance Storage Products, this story is applicable to multiple industries, including pharmaceuticals.